What 0.08 Actually Means Under Texas Law

The legal alcohol limit in Texas is 0.08. A driver 21 or older with an alcohol concentration of 0.08 or more is intoxicated as a matter of law under Texas Penal Code §49.01(2)(B), with no further proof of impairment required.

Three things about that number surprise most people:

• It is not the only way to be convicted. You can be charged below 0.08.
• It is not the same number for every driver.
• A reading of 0.15 or more is a different, more serious charge.

What Per Se Means

Per se is Latin, and in this context it means “by itself.” A per se limit is a number that carries a legal conclusion on its own, with no further argument required.

That is what 0.08 does in Texas. If the State proves you had an alcohol concentration of 0.08 or more, you were intoxicated as a matter of law. Nobody has to show you were swerving, or slurring, or failing a balance test. The number is the finding.

It works in the other direction too, and this is the part people get wrong. Because the number is one way of establishing intoxication rather than the definition of the offense, being under it does not establish the opposite. A 0.06 does not mean you were not intoxicated. It means one of the two routes to a conviction is closed and the other one is still open.

The Two Definitions of Intoxication

This is the correction the page exists to make, so here is the statute. Texas Penal Code 49.01(2) defines “intoxicated” as either:

(A) not having the normal use of mental or physical faculties by reason of the introduction of alcohol, a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body; or

(B) having an alcohol concentration of 0.08 or more.

Either one is enough. They are alternatives, not a two-part test.

The loss of normal use route requires no number at all. It is proved with the officer’s observations, the field sobriety testing, the video, your driving, and how you spoke and moved. A person who never took a test, or whose test came back low, can be prosecuted entirely on that evidence.

There is a procedural consequence that shows how alternative these really are. Texas courts treat the two definitions as evidentiary matters rather than as separate ways of committing the offense, so the State does not have to say in the charging instrument which one it intends to prove. It can simply allege that you were intoxicated and decide later. A complete defense has to answer both, not just the number.

The offense itself, and what the State has to establish beyond intoxication, is on What Is a DWI.

Can You Be Charged Under 0.08?

Yes. This question gets asked constantly and the answer is not complicated, only counterintuitive.

The 0.08 figure is a floor for one route to a conviction, not a floor for being charged. If the officer’s observations and the field sobriety evidence support the loss of normal use prong, a case can be filed on a 0.06, or on a 0.04, or on no test at all. Prosecutors do file those cases.

What changes below 0.08 is not whether a charge is possible but what the State has to work with. Without the number, the case rests entirely on human observation and video, which is a very different case to defend than one built around a laboratory result.

Deandra has answered this exact question in the Ask Deandra series, from the perspective of someone who blew under the limit and got arrested anyway: Can I Be Arrested for DWI in Texas if I’m Under 0.08?

How the State Proves a Case With No Number

A meaningful share of Texas DWI cases have no chemical test result at all. The driver refused, no test was ever offered, or the result came back under the limit and the State went ahead on the other prong. Those cases get built out of five things, and it is worth knowing what each one is actually worth.

The driving. Weaving, drifting between lanes, driving well under the limit for no reason, a wide turn, a late stop. This is often the most persuasive evidence a jury sees, because it is the only part that happened before anyone knew a police officer was watching. It is also the part that has to independently justify the stop in the first place, which is a separate question covered on The Traffic Stop.

The officer’s observations. The odor of alcohol, red or watery eyes, slurred speech, fumbling for a license, the way you got out of the car. Every one of these is subjective, and every one has ordinary explanations. An odor establishes that you drank something, not how much and not whether it affected you. Red eyes come from allergies, smoke, contact lenses, and being awake at two in the morning. Slurred speech comes from fatigue, anxiety, a speech pattern, or a medical condition. None of it is measured, and none of it is recorded anywhere except in a report the officer wrote afterward.

What you said. Naming the bar, admitting to “a couple of drinks,” estimating when you stopped drinking. All of it goes in the report and all of it comes back at trial. You are required to provide your license, registration, and proof of insurance. You are not required to answer questions about where you have been or what you have consumed.

The field sobriety tests. In a no-number case these carry more weight than they do anywhere else, which cuts both ways. When the roadside exercises are the primary evidence of impairment, every deviation from the standardized administration matters proportionally more. What the officer was counting, and what invalidates the count, is on Field Sobriety Tests and Conditions That Cause Sober People to Fail.

The video. The dashcam and body camera footage is the only part of this list that is not filtered through the officer’s memory and word choice. It frequently shows something different from the report: a person who walked steadily, spoke clearly, and followed instructions, described in writing as unsteady and confused. Getting the complete unedited footage, early, is the single highest-value step in a no-test case, and it is covered on Video and Evidence Preservation.

The honest summary is that a no-number case is harder for the State and better for the defense than most people assume. There is no laboratory result to overcome. The jury is asked to decide, beyond a reasonable doubt, whether a stranger’s roadside impressions prove you had lost the normal use of your faculties. That is a genuinely higher bar than pointing at a number above a line, and it is why a result under 0.08 substantially improves a defendant’s position even though it does not end the case.

What “BAC” Stands For

BAC is short for blood alcohol concentration. It is the term everyone uses, including officers and prosecutors, and it is not the term the statute uses.

Texas Penal Code 49.01 says alcohol concentration, and it defines that across three specimens: blood, breath, and urine. The word “blood” in BAC is doing no work when the case was built on a breath machine, because no blood was ever measured. What the instrument reported was a breath figure the law treats as equivalent to a blood figure.

That is not a vocabulary complaint. “Blood alcohol concentration” sounds like a direct measurement of what was in your blood, and in a breath case it is not one.

The Units

The two numbers Texas uses look identical and are measuring different things. Under Penal Code 49.01, an alcohol concentration means either 0.08 grams of alcohol per 100 milliliters of blood, or 0.08 grams of alcohol per 210 liters of breath.

Those are not the same measurement expressed twice. One is a concentration in a liquid, the other is a concentration in a gas, and the reason they can be set at the same figure is an assumed conversion between the two, which is examined on Partition Ratio Variability.

While Driving, Not While Testing

Here is the gap that matters most, and almost nothing published about the Texas limit says it clearly.

The offense is being intoxicated while operating a motor vehicle. The definition of intoxicated includes having an alcohol concentration of 0.08 or more. Put those together and the question a jury answers is what your alcohol concentration was when you were behind the wheel, not what it was in a room at the police station an hour or two later.

Your test result is evidence of that earlier figure. It is not the figure itself.

That distinction has teeth because alcohol concentration moves. It rises during absorption and falls during elimination, and a breath or blood test happens after a stop, field sobriety testing, transport, and a waiting period. If you were still absorbing while driving, the number that came back later can be higher than the number that existed at the only moment the law cares about. That argument is on Rising BAC Defense, and the State’s attempt to work backward from a test to a driving-time figure is on Retrograde Extrapolation.

How Many Drinks Is 0.08?

There is no honest answer to this question, and the reason is worth understanding rather than working around.

The same two drinks produce different alcohol concentrations in different people, and different concentrations in the same person on different days. The variables that move it include body mass and composition, sex, how much time has passed since the first drink and since the last, whether there was food in your stomach and what kind, how fast the drinks were consumed, and how much alcohol each drink actually contained, which varies enormously between a light beer and a poured cocktail.

Those factors interact rather than adding up neatly, which is why no chart predicts an individual result. A table that tells you a certain number of drinks keeps a certain sized person under the limit is not describing a fact about your body. It is describing an average, and being average is not something you can verify in advance or rely on afterward.

There is a second reason not to publish one. A chart of that kind reads as guidance on how much you can drink and still drive, and no amount of fine print changes how it gets used. The only figure with no uncertainty in it is zero.

The Standard Drink, and Why It Comes Up in Court

There is one place a drink count does carry weight, and it is not on the road. It is inside the State’s alcohol calculations. Forensic analysts work from a defined unit called a standard drink, quantified in the current national guidelines as 5 ounces of wine at 12% ABV, 12 ounces of beer, ale, or cider at 5% ABV, and 1.5 ounces of spirits at 40% ABV.

Those volumes are worth watching in testimony, because analysts sometimes work from local, non-standard volumes instead. A poured cocktail or a strong craft beer is frequently more than one standard drink, so the number of standard drinks an expert credits you with moves the estimate their calculation produces.

The companion folk rule, that the liver clears about one drink an hour, is a rounding of something that is not fixed. Elimination rates vary from person to person, and the current guidelines direct analysts to use a range rather than a single figure, generally 0.01 to 0.025 grams per deciliter per hour, with higher rates documented in chronic drinkers. An expert who selects one number out of that range and presents it as the rate has made a choice, not a measurement. What that choice does to a case is on Retrograde Extrapolation.

0.15 and What Changes

A result at or above 0.15 does more than strengthen the State’s case. It raises the charge. A first DWI that would ordinarily be a Class B misdemeanor is filed as a Class A when the alcohol concentration reaches that threshold, which increases the maximum penalties, and it triggers additional consequences including ignition interlock requirements.

The 0.15 threshold also works differently from the 0.08 element in a way that surprises people: it keys off what the analysis of the specimen showed, rather than off a figure that had to exist while driving. That difference is not a technicality, because it means the same timing gap that helps at 0.08 does not operate the same way at 0.15.

What the higher charge carries is covered on DWI 0.15 or Higher.

The Other Limits

The 0.08 figure is the general rule for most drivers. Two groups face stricter standards.

Commercial drivers are held to 0.04 while operating a commercial vehicle, half the general limit, and the licensing consequences of a DWI for a commercial driver reach well beyond the criminal case. See DWI and Your CDL.

Drivers under 21 are subject to Texas’s zero tolerance rule, under which any detectable amount of alcohol can support a charge. There is no threshold to fall below. See DWI vs DUI in Texas, which covers the underage rules.

No Limit Applies to Drugs

There is no per se number for drugs in Texas. No statute says that a particular concentration of a controlled substance in your blood makes you intoxicated as a matter of law, the way 0.08 does for alcohol.

That changes how those cases are proved. Without a number to point to, the State works entirely through the loss of normal use prong, which puts far more weight on observation, officer testimony, and the interpretation of what a drug concentration means about a person’s faculties. See Driving Under the Influence of Drugs.

How the Number Was Produced

Whatever figure appears in your file came out of a specific process, and the process is where the questions are. A breath result comes from an instrument at the station and involves an assumed conversion between breath and blood. A blood result comes from a draw, a tube, a chain of custody, and a laboratory analysis, each with its own failure points and none of them shared with the breath side.

Both processes are described in detail on The Breath Test and The Blood Test.

Urine is the third specimen Texas recognizes. Both the definition of alcohol concentration and the 0.15 provision name blood, breath, or urine, so a urine result can carry the same legal weight as the other two. It reaches that figure through a further set of assumptions about what a urine concentration says about the blood at the time of driving, which is a longer chain than either of the other specimens requires.

What the Number Carries

The figure in your case does more than establish an element. It sets the level of the charge, affects the punishment range, drives conditions like ignition interlock, and shapes what a prosecutor is willing to offer. What follows from each threshold is on Texas DWI Penalties.

Common Questions

Texas Legal Limit FAQ

What is the legal limit for alcohol in Texas?

The legal limit in Texas is 0.08, meaning 0.08 grams of alcohol per 100 milliliters of blood or per 210 liters of breath. A driver at or above that number is intoxicated as a matter of law, and the State does not have to prove impairment separately.

Can you be charged with DWI under 0.08 in Texas?

Yes. Texas defines intoxication two ways, and the second has no number in it: losing the normal use of mental or physical faculties because of alcohol, a drug, or a combination. A driver under 0.08, or with no test at all, can still be charged on that definition.

What is the legal limit for a commercial driver in Texas?

0.04 while operating a commercial vehicle, half the general limit. The licensing consequences of a DWI for a commercial driver reach well beyond the criminal case.

What is the legal limit for drivers under 21 in Texas?

There is no threshold to fall below. Texas applies a zero tolerance rule to drivers under 21, under which any detectable amount of alcohol can support a charge.